Transformer tank



Patented Nov. 9, 1926.

ROBERT rare QLFFIC.

TRANSFORMER COMPANY, A CORIPORATION OF PENNSYLVANIA.

TRANSFRIVIER TANK.

Application' led March 7, 1923.

. Y expansion tank from freezing in cold weather will appear from kthe following'speciiication taken in connection with the accompanying drawings, in which- Fig. 1 is a diagram showing in outline a y vertical sectional View of a transformer tank illustrating the invention.

Fig. 2 is a section online 2`-2 of Figfl, and

F igs.l 3 and 4; are vertical sectional views of modified forms of expansion tanks.

In the specific embodiment of the invention shown in the drawings a main tank 5 containing a transformer immersed in oil is provided with an'expansiontank 6 connected to the main tank by a pipe 7 so that when the transformer heats up in operation the expanding oil will pass through this pipe 7 into the expansion tank 6. The tank 6 is rectangular in cross section as shown in Fig.

2 so that a protective float 8 on the surface of the oil may freely rise and fall with the oil level.y The top of the tank 6 has a removable cover 9 fastened in place by clamps 10l and carrying va breather connection` 11 keeping ,the Vair-space 19 over .the oil in the expansion tank at atmospheric pressure.

In order to protect the oil in the expansion tank 6 from Vthe accumulation of moisture from the -air above it, .the expansion tank is provided with heating means located preferably at y the bottom of the tankk as shown in Fig.'1 or adjacent that part of the tank which is specially formed to trap the moisture as shown in Fig. 3 or in the air space 19 above the oil as indicated in Fig. 4.

In the drawings this heating means is diagrammatically illustrated as comprising an electric heating element 12in a tubular compartment 13 running along the bottom of the tank 6, this element 12 being supplied with current from a Winding 14: of a small transformer 15, the primary winding 16 of which serial no. 623,384.

may for example be connected into the secondary transformer circuit as shown.

The heat for the heating element may be supplied in any other convenient Way, as for instance by a steam connection Where a steam main is available. In the system shown in the drawings a port-ion 20 of the primary winding 16 of the transformer 15 is in series with the secondary circuit from the secondary winding 18 of the main transformer, in`

dicated diagrammatically in Fig. 1, so that normally no current will flow through this portion 2O when there is no secondary load. Another connection 17 from the remainder 21 of this primary Winding 16 connects this remaining portion 21 across a few coils or the secondary 18 of the main transformer to supply current to at least a portion of the winding` 16. at all times. The relative sizes of the portions 20, 21 and the primary winding 16 of the heating transformer may be varied depending upon theV elect desired, and either of ythese portions of the Winding may be omitted.A

The degree of heating is such that the moisture is driven out and prevented from depositing or accumulating in the oil in the expansion tank so that When this oil returns to the main tank upon cooling of the latter it will be dry and free from moisture.l

The float 8 protects the surface of the oil in the expansion tank 6 from contact with the air in the space 19` above it and avoids oxidation of the oil in the expansion tank. A plurality of heating tubes 13 may be used as indicated in Fig. 2 distributed as desired in the tank 6. K

The breather 11 is preferably supplied with filtering material 22 through which the air must pass in going into and out of the space 19. The heating of the oil in the tank 6 also heats the air in the space 19 above the surface of the oil so that the air driven out through the filtering material 22 is heated and thoroughly dries this filtering material of any previously accumulated-moisture. A further protection against the presence of moisture in the oil of the expansion tank is the trap 30 provided by the plate or partition 27 extending across the tank and positioned beneath the entrance opening of the breather 11. This plate is preferably inclined leading to a sump 28 drained by a cock29. This trap partition 27 forms an isolated chamber above it which tends to lll() catch any moisture and particularly any moisture entering through the breather connection 11 and prevents it from entering the oil.

In the modification illustrated in Fig. 3 the expansion tank 6 is provided with a sump chamber 26 below the bottoni of the tank so that any moisture will tend to gravitate into this sump chamber. Moisture in such a chamber is in constant contact with the oil with a tendency to recontaininate it and with transformers exposed outside in cold weather there is constant danger of this moisture freezing and by its expansion breaking open the expansion tank. By the addition of a heating coil 32 in the heating cham ber 33 around this sump chamber this sump chamber may be warmed so as to prevent the freezing of its contents or further heated so as to drive off the moisture and prevent vit from accumulating. The terminals of this heating coil 33 are preferably connected to the secondary of a heating transformer similar to that shown at l in Fig. 1.

In Fig. et the heating tube 43 is located in the air space 19 above the surface of the oil in the tank (i heating this aii` and warming the tank so as to drive off and prevent the deposit of moisture. Upon the rise 'of the level of the `oil the heated air in space 19 is driven out through the filtering material 22 and breather llthoroughly drying this material so that upon the subsequent contraction of the oil and the lowering of its level in the expansion tank the air passing into the space 19 will be thoroughly dried by this liltering material.

lVliile this invention has been illustrated .in connection with specific embodiments shown in the drawings, it is not coniined thereto. The heating element, for instance, may be placed in any desired position in the expansion tank and the degree and variation of the heating effect regulated in any lpreferred manner, or other modifications may be resorted to within the scope of the appended claims.

I claim 1. The combination with an auxiliary eX- pansion tank for the overflow of oil from a transformer tank, of heating means for heating a portion of said expansion tank,

and a protective float member floating on the surface ofthe oil in rsaid expansion tank.

2. An auxiliary expansion tank for the overflow of oil from the transformer tank, comprising a tank body, heating means therefor, and a breather connection from the interior of said expansion tank to the air, said breather comprising a filtering material to exclude moisture from 'said tank.

3. An auxiliary expansion tank for the overflow of oil from the transformer tank, comprising a tank body, heating means there- -for, a breather connection from the interior 'el' said Vexpansion tank to the air, said breather comprising a filtering material to exclude moisture from said tank, and a protective iio'at member adapted to freely float on the surface of the oil in said expansion tank.

t. In an expansion tank for the overflow of oil from a main transformer tank the combination with means forming an air space above the level of the oil in said expansion tank, of a trap chamber adapted to collect moisture from said space so as to prevent it from entering said oil.

5. In an expansion tank for the overflow of voil from a main transformer tank the combination with means forming an air space above the level of the oil in said eX- pansion tank, a breather connection maintaining said space in communication with the atmosphere, and a moisture trap chamber within said expansion tank and beneath the entrance of said breather connection adapted to collect moisture so as to prevent it from ventering the oil in said expansion tank.

6. The combination with a tank adapted to contain cooling oil for a transformer, of heating means in the oil of said tank, a space above the level of the oil in said tank, and a trap chamber adapted to collect moisture from said space so as to prevent it from entering said oil.

7. The combination with an auxiliary eX- pansion tank for the overflow of oil from the transformer tank, of heating means within the oil of said tank, a space above the level of the oil in said expansion tank, and a trap chamber adapted to collect moisture from said space so as to prevent it from entering said oil.

8. In an expansion tank for the overflow of oil from the main transformer tank, the combination with means forming a space above the level of the oil in said expansion tank, heating means in said expansion tank, and a trap chamber adapted to collect moisture from said space so as to preventit from entering said oil.

ROBERT v BINGAY. 

